Transmit power stuck near 15 dBm on a small PCIe adapter
A user could not raise the transmit power of a small PCIe 802.11n adapter above about 15 dBm. At that level the connection became very unstable once away from the access point.
The reporter wanted to know whether the limit came from the driver, the regulatory settings or the hardware itself. The report records no confirmed answer.
Takeaway. Regulatory limits, antenna gain and driver power tables all cap output. Check the regulatory domain and the configured limit before assuming a fault.